Effect of Repeated Injection of Iodixanol on Renal Function in Healthy Wistar Rats Using Functional MRI.

<italic>Purpose</italic>. To determine the optimal time interval of repeated intravenous injections of iodixanol in rat model and to identify the injury location and causes of renal damage<italic> in vivo</italic>.<italic> Materials and Methods</italic>. Rats were randomly divided into Control group, Group 1 with one iodixanol injection, and Group 2 with two iodixanol injections. Group 2 was subdivided into 3 cohorts according to the interval between the first and second iodixanol injections as 1, 3, and 5 days, respectively. Blood oxygen level-dependent (BOLD) imaging and diffusion weighted imaging (DWI) were performed at 1 hour, 1 day, 3 days, 5 days, and 10 days after the application of solutions.<italic> Results</italic>. Compared with Group 1 (7.2%), Group 2 produced a remarkable R2⁎ increment at the inner stripe of the renal outer medulla by 15.37% (P=0.012), 14.83% (P=0.046), and 13.53% (P>0.05), respectively, at 1 hour after repeated injection of iodixanol. The severity of BOLD MRI to detect renal hypoxia was consistent with the expression of HIF-1<italic>α</italic> and R2⁎ was well correlated with HIF-1<italic>α</italic> expression (r=0.704). The acute tubular injury was associated with urinary NGAL and increased significantly at 1 day.<italic> Conclusions</italic>. Repetitive injection of iodixanol within a short time window can induce acute kidney injury, the impact of which on renal damage in rats disappears gradually 3–5 days after the injections. [ABSTRACT FROM AUTHOR]